The distance between City C and City D was 780 km apart. A lorry travelled at an average speed of 81 km/h from City C to City D. At the same time, a bus travelled at an average speed of 75 km/h from City D to City C. How much further did the lorry travel than the bus when the lorry met the bus on the way?
Combined speed of the lorry and the bus
= 81 + 75
= 156 km/h
Time taken for the lorry and the bus to meet
= 780 ÷ 156
= 5 h
Difference in the speed between the lorry and the bus
= 81 - 75
= 6 km/h
Distance that the lorry travelled further than the bus
= 5 x 6
= 30 km
Answer(s): 30 km